package com.atguigu.nio;

import java.io.IOException;
import java.net.InetSocketAddress;
import java.nio.Buffer;
import java.nio.ByteBuffer;
import java.nio.channels.ServerSocketChannel;
import java.nio.channels.SocketChannel;
import java.util.Arrays;

/**
 *  Scattering 将数据写入到buffer时，可采用buffer数组，依次写入 【分散】
 *  Gathering 从buffer读取数据时，可采用buffer数组，依次读
 */
public class ScatteringAndGatheringTest {

    public static void main(String[] args) throws IOException {

        // 使用ServerSocketChannel和SocketChannel
        ServerSocketChannel serverSocketChannel = ServerSocketChannel.open();
        InetSocketAddress inetSocketAddress = new InetSocketAddress(7000);

        // 绑定端口到socket并启动
        serverSocketChannel.socket().bind(inetSocketAddress);

        // 创建buffer数组
        ByteBuffer[] byteBuffers = new ByteBuffer[2];

        byteBuffers[0] = ByteBuffer.allocate(5);
        byteBuffers[1] = ByteBuffer.allocate(3);

        // 等待客户端连接
        SocketChannel socketChannel = serverSocketChannel.accept();

        int messageLength = 8;
        // 循环读取
        while (true) {
            int byteRead = 0;

            while (byteRead < messageLength) {
                long read = socketChannel.read(byteBuffers);
                byteRead += read;
                System.out.println("byteRead=" + byteRead);
                // 使用流打印
                Arrays.stream(byteBuffers).map(buffer -> "position=" + buffer.position() + "，limit=" + buffer.limit()).forEach(System.out::println);
            }

            // 将所有的buffer反转
            Arrays.stream(byteBuffers).forEach(Buffer::flip);

            // 将数据读出显示到客户端
            long byteWrite = 0;
            while (byteWrite < messageLength) {
                long write = socketChannel.write(byteBuffers);
                byteWrite += write;
            }

            // 将所有buffer进行clear
            Arrays.stream(byteBuffers).forEach(Buffer::clear);


            System.out.println("byteRead=" + byteRead + "，byteWrite=" + byteWrite + "，messageLength=" + messageLength);
        }


    }

}
